Access ramp having self-contained hydraulics and improved bushing assembly

ABSTRACT

Therefore it may be seen that the present disclosure includes the description of a system, particularly the First System  100,  which include advantages over the known prior art by providing a wheelchair ramp subassembly which includes the use of internal hydraulics, such that the subassembly can use its own hydraulics which do not need to be shared with other hydraulic units on the supporting vehicle. This provides an apparatus that includes improved operating characteristics, tends not to be contaminated through shared hydraulic connections, and can operate conditions in a manner not possible if connected to a shared hydraulic system. An improved bushing  1005  is also provided.

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of provisional patentapplication Serial No. 60/359,922 filed Feb. 27, 2002. The presentapplication claims the full benefit and priority of said application,and incorporates the entire contents of same by reference.

FIELD OF THE INVENTION

[0002] The present invention relates generally to ramps, and moreparticularly relates to ramps used to provide access to vehicles. Suchvehicle ramps are sometimes known as “wheelchair ramps” and can beselectively moved in and out of place in order to allow selective accessby wheelchairs from surfaces such as sidewalks or streets.

BACKGROUND OF THE INVENTION

[0003] Wheelchair ramps are often used in order to allow wheelchair orstepless access to a bus or similar vehicle. Such ramps typically haveto be deployed from a retracted position to an extended position. Theyare usable in the extended position. Such mechanisms encounteroccasional rough handling and this have to be resilient, yet they needto operate in a smooth, controlled, and reliable manner. Improvements tosuch systems are always in demand.

SUMMARY OF THE INVENTION

[0004] In summary, the present invention relates to the use of internalhydraulics in a wheelchair ramp subassembly, and also relates to the useof an improved bushing assembly.

[0005] Generally described, the present invention is directed towardsthe use of internal hydraulics in a wheelchair ramp subassembly, suchthat the subassembly can use its own hydraulics which do not need to beshared with other hydraulic units on the supporting vehicle.

[0006] More particularly described, the present invention is directedtowards use of internal hydraulics in a wheelchair ramp subassembly, inwhich said internal hydraulics include the use of hydraulic fluid whichincludes different characteristics than the hydraulic system included inthe main vehicle (e.g., the bus).

[0007] More particularly described, the present invention is alsodirected towards use of an improved bushing assembly which is reliableyet tamper resistant.

[0008] Therefore, it is an object of the present invention to provide animproved wheelchair ramp subassembly for use in a supporting vehicle.

[0009] It is a further object of the present invention to provide animproved wheelchair ramp subassembly for use in a supporting vehiclesuch as a bus.

[0010] It is a further object of the present invention to provide animproved wheelchair ramp subassembly which is efficient in operation.

[0011] It is a further object of the present invention to provide animproved wheelchair ramp subassembly which is reliable in operation.

[0012] It is a further object of the present invention to provide animproved wheelchair ramp subassembly which is effective in operation.

[0013] It is a further object of the present invention to provide animproved wheelchair ramp subassembly which can withstand certainenvironmental rigors such as cold temperatures.

[0014] Other objects, features, and advantages of the present inventionwill become apparent upon reading the following detailed description ofthe preferred embodiment of the invention when taken in conjunction withthe drawing and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Having thus described the invention in general terms, referencewill now be made to the accompanying drawings, which are not necessarilydrawn to scale.

[0016]FIG. 1 is a pictorial view of the modular wheelchair rampsubassembly 10 (a.k.a. modular wheelchair ramp assembly 10) according tothe present invention, configured to be placed into service into a bus(not shown in this figure but shown in FIG. 14) or other suitablevehicle.

[0017]FIG. 2 is an exploded view which illustrates both the First System100 (if element 60 is used) and the Second System 200 (if element 201 isused).

[0018]FIG. 3 is a pictorial view showing an assembled, and adisassembled, view of linkages used in conjunction with the bushing1000.

[0019]FIG. 4 is a pictorial view, both assembled and disassembled, of aconfiguration which includes the use of the bushing 1000, and anassociated shim washer 1001 and roll pin 1002.

[0020]FIG. 5 is an illustrated view illustrating the various elements ofthe bushing assembly 1005, including bushing 1000, shim washer 1001 androll pin 1002.

[0021]FIG. 6 is an isolated pictorial view of the bushing 1000 accordingto the present invention, including head section 1100, bearing section1200, and fixing section 1300.

[0022]FIG. 7 is a perspective, as well as plan and elevational views ofthe bushing 1000 according to the present invention. The dimensionsshown are for illustrative purposes only and should not be construed aslimiting.

[0023]FIG. 8 is a pictorial installation of the bushing 1000 accordingto the present invention, shown in conjunction with two linkage members.It should be understood that the shim washer 1001 and roll pin 1002 arenot shown in this view.

[0024]FIG. 9 is a view similar to that of FIG. 8, except in thisinstance, bushing 1000 is shown installed, the shim washer 1001 is notshown (it is concealed), and the roll pin 1002 is in the process ofbeing inserted.

[0025]FIG. 10 is a view similar to that of FIG. 9, with a slightly widerangle view, with the roll pin 1002 shown in its installed position,which as may be seen is difficult to tamper with without the propertools.

[0026]FIG. 11 is an illustration of the use of the bushing 1000according to the present invention (shown held by a human hand), used inconjunction with a “wrist”-type connection in which an elongate memberis attached to a ramp side flange 31. In this view, the bushing 1000 isshown, but the shim washer 1001 and roll pin 1002 are not shown.

[0027]FIG. 12 is a pictorial view showing the bushing 1000 in itsinstalled configuration, with the roll pin 1002 being positioned forinstallation and the shim washer concealed.

[0028]FIG. 13 is a view similar to that of FIG. 12, except the roll pin1002 is installed. Note the floor of the ramp in the bottom left sectionof the drawing.

[0029]FIG. 14 is a illustrative view of a bus 9 or other vehicleincluding a first set of hydraulics 8 which operate elements such aspower steering for the front wheels 7 and which also includes a secondset of hydraulics which operate a modular wheelchair ramp subassembly10.

[0030]FIG. 15 is a hydraulic schematic for the First System 100.

DETAILED DESCRIPTION OF THE INVENTION

[0031] The present invention now will be described more fullyhereinafter with reference to all of the accompanying drawings, figures,and photographs in which preferred embodiments of the invention areshown. This invention may, however, be embodied in many different formsand should not be construed as limited to the embodiments set forthherein; rather, these embodiments are provided so that this disclosurewill be thorough and complete, and will fully convey the scope of theinvention to those skilled in the art. Like numbers refer to likeelements throughout.

[0032] The invention relates specifically to hydraulically drivenwheelchair ramp assemblies, such as assemblies that are relativelyself-contained units which are installed as a unit into a bus or othersimilar vehicle.

[0033] First, two ramp assembly systems will be discussed separately, aFirst System 100 and a Second System 200. Although a “bus” may be usedas an example of a vehicle with which the ramp assemblies may be used,it may readily be understood that other vehicles may be used whichinclude the use of a ramp assembly without departing from the spirit andscope of the present invention.

[0034] I. First System 100

[0035] Generally described, the first wheelchair ramp subassembly system10 includes the following elements:

[0036] Basic framework 20

[0037] Pivoting ramp 30

[0038] Framework top cover 40

[0039] Rotary actuator 50

[0040] Linkage assembly (including linkages) 56

[0041] Hydraulic pump subassembly 60

[0042] Control system 70

[0043] More details will now be discussed.

[0044] Framework 20

[0045] The framework 20 is configured to be attached relative to theframework of a bus (see FIG. 14) or other suitable vehicle. Thisframework 20 is also configured to support various elements of thesubassembly, including the elements 30, 40, 50, 56, 60 and 70.

[0046] Reference is particularly made to FIG. 2, which shows framework20 (also denoted as “T7100” in FIG. 2), which includes a generallyrectangular perimeter made of elongate frame members, within whichvarious generally elongate “rib”-type members extend. All of thesevarious elongate members will be generally referred as “frame members.”

[0047] Pivoting Ramp 30

[0048] The pivoting ramp 30 is configured to be pivotably attachedrelative to the “front” edge of the framework, such that it pivots aboutramp pivot axis RPA shown in FIG. 1.

[0049] This ramp is generally conventional, and pivots from a withdrawn,stored, position to an extended, enabled, position. The ramp isconfigured to support the weight of a user; depending on the position,the user will contact one or the other side of the ramp.

[0050] As may be seen in FIG. 1, the ramp 30 includes two side flanges31, which extend upwardly at a generally 90 degree angle from the rampfloor. These side flanges are substantially platelike in that they havea substantially nominal thickness defined by two opposing primary planarsurfaces lying in parallel planes. In each instance one primary planarsurface faces away from the ramp path and the other primary planarsurface faces the ramp path and serves as a containment guide should thewheelchair tend to veer off the ramp.

[0051] Top Cover 40

[0052] The top cover 40 is configured to be removably attached to thetop of the framework to conceal and contain various elements locatedtherein. The cover is also configured to support the weight of a userwhen the ramp is extended.

[0053] Rotary Actuator 50

[0054] The rotary actuator 50 is configured to convert hydraulicpressure, provided to its two input ports, into rotary motion. Twohydraulic lines go into the input ports rotary actuator, one line goinginto each end.

[0055] This actuator 50, has an output shaft configured to rotate ineither direction. Upon receipt of pressure in a “first” input port,rotation is in a “first” direction. Upon the direction of high pressurein a “second” input port, rotation is in a second direction, which isopposite to the first direction.

[0056] As will be seen in later discussion, such alternating rotation isused to alternately extend and withdraw the ramp, though the use ofsuitable linkages intermediate the output shaft at the rotary actuator50 and the pivoting ramp 30. In one configuration, the line that comesin towards the rear of the ramp, furthest inside the bus, is the onethat gets pressurized when the ramp opens.

[0057] Linkage Assemblies 56

[0058] These are two-segmented, linkage assemblies 56 with one linkage56L (a.k.a. the “long arm”) having one end rigidly attached to the shaftof the rotary actuator, and the second end of the first segmentpivotably attached to the first end of the second segment 56S. Thesecond end of the second segment 56S (a.k.a. the “short arm”) ispivotably attached to the ramp. Operation is conventional, although aninventive bushing assembly 1005 described later may be used to provideimproved pivoting functions as later described. These linkages likewisemay be seen to be platelike, and are defined by two opposing primaryplanar surfaces lying in parallel planes.

[0059] Hydraulic Pump Subassembly 60

[0060] The hydraulic pump subassembly 60 is configured to convertelectrical power into hydraulic pressure, output to one of two hydraulicports.

[0061] The hydraulic pump assembly 60 includes an electrical motor(preferably configured to accept DC current (e.g. 24 volt) from thevehicle), the electrical motor driving a hydraulic pump. Also includedis a solenoid valve configured to control to which of the two hydraulicparts the hydraulic pressure is provided. Also provided is a suitablereservoir, within which a gear or other suitable pump is located).

[0062] Operation at this solenoid valve is provided by an electricalcontrol line, operably attached to the control system 70, as discussedlater.

[0063] The two hydraulic ports of the hydraulic pump subassembly areconnected to two hydraulic lines that lead to two corresponding ports onthe rotary actuator. By suitably controlling the solenoid valve,hydraulic pressure can be supplied to either of the two hydraulic lines,thus selectively rotating the rotary actuator in the desired direction.It may be understood that when one of two connecting lines is the “highpressure” line, the other is the “low pressure” line which returns fluidto the pump subassembly 60. Pressure bypass is internal to this unit.

[0064] The pump subassembly 60 is mounted to one of the frame members ofthe frame with a couple of bolts. For example, on one of the side framemembers on the left side, two bolts pass through a spacer and then rightinto the pump; there are two boltholes in the side of the pump. FIG. 1is a cut away view looking from the top and showing where the pumpsubassembly 60 is mounted; the viewer can actually see the rib it ismounted to.

[0065] When mounted in the nature described above, the longitudinal axisof the DC motor of the pump subassembly 60 is substantially parallel tothe walking path direction.

[0066] Control System 70

[0067] The control system 70 is configured to control the operation ofthe overall ramp subassembly 10.

[0068] The control system 70 has an input (typically supplied bysuitable controls in the operator's region) which includes an “Extend”and a “Retract” signal. When either of those signals is received, thesystem 70 causes the pump in the pump subassembly 60 to begin pumping.Directional control of the fluid is provided by reversing the electricalmotor, which is done by reversing its polarity by use of a suitablerelay.

[0069] As may be understood, this allows an operator to operateextension and retraction of the ramp.

[0070] Hydraulic Schematic (See FIG. 15)

[0071] Reference is now made to FIG. 15, which shows a hydraulicschematic of the First System. For purposes of discussion of this figureonly this shows the following elements:

[0072] “1”—Bypass 2-way switch

[0073] “2”—Relief Valve

[0074] “3”—Check Valve

[0075] “4”—Pump

[0076] “5”—DC Motor

[0077] “6”—Reservoir

[0078] “7”—Orifice

[0079] The element “1” is spring loaded to allow for passage of fluidtherethrough when in the shown position, but not to allow fluid passagewhen in an “energized” position which moves the switch body upwardlyagainst the spring. As will be discussed later, this energizing is donewhen the DC motor is energized in either of its two rotationaldirections.

[0080] The two items “2” allow for pressure relief should the rotaryactuator (which drives the ramp) becomes blocked (typically when theramp is blocked).

[0081] The check valves “3” are essentially one-way valves which preventfluid passage back down into the reservoir “6”.

[0082] The two orifices “7” are in fact modified one-way valves, eachmodified with a drilled 0.010 inch hole to provide relatively free flowin one direction, with a 0.010 hole presented in the opposite direction,providing flow control.

[0083] The pump “4” is driven by a reversible DC motor “5”, such that byreversing the polarity of the motor, fluid can be pumped to the selectedone of the two lines to the rotary actuator. When the motor isenergized, regardless of the direction, the element “1” is energized tocause movement of the element “1” to the position not shown, whichresults in no flow through element “1”.

[0084] When the motor “5” is not energized (power off), the element “1”goes to the position shown, and the rotary actuator (and the ramp) canbe moved manually (such as may be needed in a power failure) withrecirculation provided by element “1”.

[0085] II. Second System 200

[0086] The Second System is hydraulically operated system, except thehydraulic fluid and the hydraulic pressure is provided by the bushydraulics system. This is the same hydraulic system which might operateother hydraulically driven components on the bus, such as a powersteering component.

[0087] Instead of a self-contained pump assembly as used in the FirstSystem, as shown in FIG. 2, the Second System includes the use of amanifold unit 201 (also denoted as T7600). This manifold unit 201 isconfigured to accept two or more hydraulic lines, including apressurized or “high side” line, as well as one or more pressurized or“low side” lines. This unit in one configuration is mounted to the backwall of the frame through some bulkhead fittings, although it can bemounted elsewhere.

[0088] III. Different Features, Actions, and Advantages Between the TwoSystems

[0089] As may be understood, the two systems include different features,actions, and advantages. Particularly, the differences will be discussedfrom the point of view of the First System versus the Second System.

[0090] Different Features

[0091] The First System 100 has its own hydraulic pump and associatedreservoir, compared to the manifold unit 201 of the Second System 200.

[0092] Bus hydraulics are not used in the First System, as the FirstSystem 100 has its own dedicated hydraulic system, which is totallyisolated from the bus hydraulics. The only thing used from the bussystem is in the First System 100 is electrical power. In both systems asimilar five- (5) cord electrical connector is provided between thesystems and the bus or other vehicle. The First System requiresadditional amperage to drive the pump, but does not require separatehydraulics. The First System 100 in one embodiment requires at least 10amps for operation. The Second System 200 could require around 2 amps.Control connections are essentially the same.

[0093] In the First System, pressure relief is in the pump housing. Inthe Second System, pressure relief is in the manifold.

[0094] Actions

[0095] The actions of the two systems are different. Compared to theFirst System 100, the Second System 200 has a tendency to “vault” out ofthe floor for a certain distance during which it would come up to highspeed, and then would be under control for the rest of its stroke. Thistendency is particularly evident when the units has been unused for aperiod of time, sufficient to allow the pressure to bleed out of therotary actuator.

[0096] The First System 100 does not tend to exhibit such vaulting;because of its construction it will have a tendency to “ramp up” inpressure, in other words to build pressure slowly, and thus come up in amore controlled fashion. This provides smooth acceleration and smoothdeceleration.

[0097] The reason for this is as follows. In the Second System 200hydraulic system, which includes a manifold and valve inside, there maybe 2000 PSI on the line coming in. If the valve is then suddenlyshifted, there can be a sudden increase of 2000 PSI on the piston on therotary actuator in a relatively short period of time (assuming bleedingover time as discussed above). Thus this tends to provide a sudden“jerking” effect.

[0098] On the First System 100, which includes its own pump, the pumpwhen first switched on (electrically) gradually builds up pressure inthe line leading to the rotary actuator. It keeps pumping and “rampingup” pressure until the ramp starts moving. This pressure buildup occursrelatively quickly (less than a second), but it is still long enough,and done in a curved type fashion, to greatly reduce the shock to thesystem, when compared to the Second System.

[0099] If for some reason mechanically the ramp is hung or otherwiseblocked, in both systems pressure would be pumped until the pressurerelease valve setting inside the pump (or the Manifold in the SecondSystem 200) will release pop and the fluid would bypass as known in theart.

[0100] Advantages

[0101] The First System 100 includes several advantages over the SecondSystem 200. The First System 100 allows use of a self-contained, moremodular, hydraulic system. This is advantageous in that the quality andtype of the fluid can be better controlled. In the Second System 200,because of use of bus hydraulics and their hydraulic fluid, the designerof the system cannot control how clean the fluid is, or the type offluid used.

[0102] As noted above, in the Second System 200 environment, the samehydraulic fluid flowing through the Second System 200 is also being usedin conjunction with other hydraulic units such as a steering mechanism.This is disadvantageous as such an orifice flow controls or the likecould be stopped up because of minute trash in the hydraulics.

[0103] Another big advantage is that the designer of the Second System200 is not limited to conventional hydraulic fluid if the ramp does nothave to share its fluid. This allows the designer the opportunity to usespecial fluid that can operate under adverse environments such as cold.For example, with the use of special cold weather hydraulic fluid (e.g.Mobil Aero HFA), the inventor performed a cold soak test, which is arequirement for this ramp to operate at minus 25 degrees instantly. Theunit passed with no warm up and no heater.

[0104] Another advantage to the First System 100 is ease ofinstallation, in that one does not have to deal with hydraulic linesfrom the bus as is the case of the Second System 200, the onlyconnections required are electrical. Typically, the bus hydraulic lineshave to come through a hole in a frame member on the bus. Unfortunately,the bus company often does not provide such required access holes inframe members at the same place twice, and this requires significantmodifications during installation of the hydraulic supply lines of theSecond System 200. In contrast, in the First System 100, electricalwiring is much easier to route and connect.

[0105] IV. Bushing Assembly

[0106] Another invention provided by applicant includes the use of abushing assembly 1005, which is configured to provide a bearing surfacesuitable for use within a pivoting connection between two relativelypivoting members. These “two relatively pivoting members” will first bedescribed in general terms, but will also be discussed in more detail byway of example.

[0107] General Environment

[0108] As will be described in later detail, the improved bushing 1000according to the present invention can be universally used in variouslocations within the pivoting ramp assembly 10 (See FIG. 1) describedabove, in a first, “wrist”-type, connection such as denoted as “W” inFIGS. 1, 3 and 13, as well as in a second, “elbow”-type, connectionbetween two elongate linkages (a.k.a. “arms”), shown as “E” in FIGS. 1,3, 4 and 10. In the first embodiment, one of these pivoting members isan elongate linkage member such as 56S, which is pivotably attachedrelative to a side flange 31 of a ramp member such as 30 in FIG. 1. Inthe second pivoting embodiment, both of these pivoting members arelinkages such as 56L, 56S from the assembly 56 in FIG. 1.

[0109] The bushing assembly provides a detachable pivoting connectionbetween two relatively pivoting members, each of which includes athrough hole, and one of which include a bore hole for a roll pin forattachment of the bushing thereto.

[0110] General Construction and Operation of Bushing Assembly 1005

[0111] Generally described, referring now to FIG. 5, the bushingassembly 1005 includes a bushing 1000, a shim washer 1001, and a rollpin 1002, all configured to be used as a coordinated group of elementsto provide a pivoting action between two relatively pivoting members, inorder that the pivoting members may pivot relative to each other alongan axis, which is substantially common to the longitudinal axis LA (seeFIG. 7) of the bushing member 1000, and likewise preferably extendsthrough the centers of the two circular through holes defined by the twopivoting members.

[0112] The bushing member 1000 (see FIGS. 6 and 7) is detachably fixedto one of the pivoting members through the use of the roll pin 1002,which extends through a roll pin bore which is partially defined by asection of the bushing member and is partially defined by the firstpivoting member. The second pivoting member, which is put into placebefore the roll pin is installed, is pivotably attached to the firstmember by use of the bushing member 1000. More particularly, the secondpivoting member is configured to rotatably pivot around a section of thebushing member 1000, but is axially captured to prevent axial movementalong the bushing member in one axial direction by a head portion of thebushing member 1000, and in the other axial direction by the presence ofthe first pivoting member.

[0113] This provides an effective, reliable, and tamperproof bushing foruse in what can be a stressful environment.

[0114] Details of the various elements of the bushing assembly 1005 arenow provided.

[0115] Bushing Element 1000

[0116] Reference is now made to FIGS. 6 and 7, which show detailed viewsof the bushing member 1000 according to one element of the presentinvention. This bushing element 1000 is composed of three sequentiallength sections, a first, “head” section 1100, a second, “bearing”,section 1200, and a third, “fixing”, section 1300.

[0117] These Sections 1100, 1200 and 1300 are, in one preferredembodiment, all part of a unified single brass element 1000, althoughother configurations are contemplated without departing from the spiritand scope of the present invention.

[0118] The head section 1100 is configured to provide a containmentfeature for the element, which is pivotably attached relative to thebushing element 1000. This head section 1100 includes an outer diameter,which is greater than the outer diameter of both the other sections1200, 1300.

[0119] The middle, bearing, section 1200 of the bushing element 1000 isconfigured to provide a bearing surface for one of the two relativelypivoting members. This bearing section 1200 includes an outercircumferencial surface, which defines an outer diameter, which islarger than the diameter of the fixing section 1300, but is smaller thanthe outer diameter of the head section 1100.

[0120] The fixing section 1300 is substantially cylindrical in shape,and is solid, with the exception of a transverse roll pin bore 1301. Thefixing section 1300 itself likewise includes an outer circumferencialsurface, which defines an outer diameter of, in the embodiment shown,0.50 inches. This outer diameter is less than the diameter of the fixingsection 1300, and thus is less than the outer diameter of the headsection 1100.

[0121] The fixing element 1300 is configured to be attached relative toone of the two relatively pivoting members by use of the roll pin 1002which extends through and is frictionally fixed relative to the fixingelement 1300, as well as to the one of the relatively pivoting members.

[0122] Shim Washer 1001

[0123] The bushing member 1000 is configured to be used in conjunctionwith a shim washer 1001, such as shown in FIG. 5, which includes aninternal hole, and a nominal thickness.

[0124] This shim washer 1001 is configured to provide a thrust bearingfeature between the two relatively pivoting elements, and preferably hasits internal bore fitting suitably about the outer diameter of themiddle, bearing, section 1200 of the bushing element 1000, wheninstalled.

[0125] The shim washer 1001 may be made of suitable brass, stainlesssteel, or other suitable material, including but not limited toplastics.

[0126] Roll Pin 1002

[0127] Elements 1000, 1001, are used in conjunction with the roll pin1002, which as described elsewhere in this application is configured tofit within a roll pin bore hole which extends through the fixing section1300 as well as one of the pivoting members to detachably fix the twotogether.

[0128] General Installation and Operation

[0129] In order to install the bushing assembly 1005 to the tworelatively pivoting members, some distinction must first be made betweenthe two pivoting members. This will be done by referencing one as afirst relatively pivoting member and the other as a second relativelypivoting member. The bushing 1000 will be fixed to the first relativelypivoting member (e.g., the ramp flange), and will pivot relative to thesecond relatively pivoting member (e.g., the short arm).

[0130] The first relatively pivoting member has a through hole and aroll pin hole, and the second relatively pivoting member has a throughhole only.

[0131] To install the bushing assembly 1005 such that it links the tworelatively pivoting members, the bushing 1000 is first positioned withinthe second relatively pivoting member, such that the bearing section1200 of the bushing 1000 is positioned within the bore of the hole ofthe second relatively pivoting member. The first relatively pivotingmember is then positioned relative to the bushing 1000 such that thefixing section 1300 of the bushing 1000 fits within the bore of largerhole of the first relatively pivoting member.

[0132] The bushing member 1000 is then angularly oriented such that itstransverse roll pin bore 1301 aligns with the roll pin bore provided inthe first relatively pivoting member. The roll pin 1002 is then pressedinto place, such that it extends both through bores, preferably in atight frictional relationship such as if the preferred function withroll pins, such that the bushing member 1000 is attached to the firstrelatively pivoting member via the roll pin 1002. Disinstallation is thereverse of installation. Therefore, it may be seen that the bushingmember 1000 pivot relative to the second relatively pivoting member, andis fixed relative to the first relatively pivoting member.

[0133] Installation and Operation in First Pivoting Connection—Arm toRamp

[0134] As noted above, the bushing assembly combines to provide asuitable detachable pivoting connection between two “relatively pivotingmembers”. In one instance, these two relatively pivoting members can bea linkage member 56S (a.k.a. the “short arm”) and a pivoting ramp member30 such as shown in FIG. 1. This type of connection could also bereferred to as a “wrist”-type connection, to facilitate pivoting betweenthe linkage member 56S and one of the side flanges 31 of the ramp member30 as the ramp member pivots relative to the overall assembly 10.

[0135] The relevant end of the linkage member 56S preferably includes ahole which is configured to mate with the outer diameter of the bearingsection 1200 of the bushing member 1000, such that the linkage member56S can pivot about the bearing section 1200 of the bushing member 1000.This hole is actually “stepped” to allow a relatively flush mounting ofthe bushing member 1000 within the linkage member 56S as shown in FIG.13.

[0136] The ramp member 30 includes two platelike side flanges 31, one ofwhich is associated with the pivoting connection under discussion. Thisside flange 31 likewise includes a through hole 34 as shown in FIG. 11,which is smaller in diameter than the hole in the above-mentionedlinkage member, said hole 34 sized to accept the outer diameter of thefixing section 1300 of the bushing member 1000. The side flange 31likewise includes a roll pin hole 35, which in one embodiment is a holewhich is drilled along an axis which is parallel to the primary planarsurfaces of the substantially platelike side flange 31, andperpendicular to the bore axis of the bushing-accepting hole in the sideflange 31. This will be also referred to as a hole “drilled through thecenter of the thickness” of the side flange 31. Such drilling is doneall the way through the flange so the roll pin can be pushed through incase of a need for removal.

[0137] Installation and Operation in Second Pivoting Connection—Arm toArm

[0138] In the second configuration, the bushing assembly 1005, which iscomprised of the bushing 1000, the shim washer 1001, and the roll pin1002, is configured to provide a pivoting connection between twoelongate linkages 56S, 56L such as shown in FIG. 10. This could bethought of as an “elbow”-type of connection using the human body as areference.

[0139] The first linkage 56L can also be considered the “long arm” andthe second linkage 56S may be considered the “short arm”.

[0140] The long arm is configured to have one end rigidly attached to areciprocating, rotating, shaft, as described above. The other end of thelong arm 56L is attached at an “elbow” type connection E to the firstend of the short arm 56S. As discussed above, the other end of the shortarm 56S is pivotably attached relative to the ramp 30, which is itselflikewise pivotably attached relative to the overall frame of theapparatus.

[0141] In the instance of the “elbow” connection, the roll pin bore holeis drilled through the long arm 56L as shown in FIGS. 9 and 10, suchthat the drilling access is substantially parallel to the primary planersurfaces of the long arm 56L, and the drill axis is likewise positionedapproximately between the opposing plainer surfaces. Furthermore, thedrill axis preferably intersects the center bore access of the hole inthe long arm 56L.

[0142] Advantages

[0143] As may be understood, the bushing assembly 1005 provides aneffective, reliable, yet relatively tamper proof configuration whichdoes not include threaded or other similar connections which can vibrateloose. The configuration 1005 also provides a relatively “clean” andsmooth configuration, which provides minimal risk of snagging.

[0144] Elements List

[0145]10 wheelchair ramp subassembly

[0146]20 Basic framework

[0147]30 Pivoting ramp

[0148]31 Ramp pivot axis

[0149]40 Framework top cover

[0150]50 Rotary actuator

[0151]56 Linkage assemblies

[0152]60 Hydraulic pump subassembly

[0153]70 Control System

[0154]100 First System

[0155]200 Second System

[0156]1000 Bushing

[0157]1001 Shim washer

[0158]1002 Roll Pin

[0159]1003

[0160]1005 Bushing Assembly

[0161]1100 Head Section

[0162]1200 Bearing Section

[0163]1300 Fixing Section

[0164] V. Conclusion

[0165] Therefore it may be seen that the present disclosure includes thedescription of a system, particularly the First System 100, whichinclude advantages over the known prior art by providing a wheelchairramp subassembly which includes the use of internal hydraulics, suchthat the subassembly can use its own hydraulics which do not need to beshared with other hydraulic units on the supporting vehicle. Thisprovides an apparatus that includes improved operating characteristics,tends not to be contaminated through shared hydraulic connections, andcan operate conditions in a manner not possible if connected to a sharedhydraulic system.

[0166] The present disclosure also discloses an improved bushingconfiguration 1005 which is effective yet relatively tamper-resistant.

1. An improvement in a vehicle for providing wheelchair access, saidvehicle having a frame and also including a vehicle hydraulic system forcontrolling the movement of said vehicle, said improvement comprising: awheelchair ramp subassembly including a ramp member pivotably attachedrelative to said frame of said vehicle; and a ramp hydraulic systemconfigured to control the pivoting action of said wheelchair rampmember, said vehicle and ramp hydraulic systems isolated from andseparated from each other such that one does not include the fluid ofthe of the other.
 2. The vehicle as claimed in claim 1, wherein saidvehicle hydraulic system includes a vehicle hydraulic fluid and whereinsaid ramp hydraulic system includes a ramp hydraulic fluid.
 3. Thevehicle as claimed in claim 2, wherein said ramp hydraulic fluid has adifferent operating characteristic than said vehicle fluid.
 4. Thevehicle as claimed in claim 1, wherein said ramp hydraulic systemincludes an electric motor which drives a pump which pressurizes saidramp hydraulic fluid, which drives said rotary actuator, which causessaid said pivoting movement of said ramp.
 5. The vehicle as claimed inclaim 1, wherein said ramp hydraulic system includes an electric motorwhich drives a pump which pressurizes said ramp hydraulic fluid, whichdrives said rotary actuator, said rotary actuator having a rotatingoutput shaft, and said wheelchair ramp assembly further comprising alinkage assembly intermediate said output shaft and said pivoting rampmember, such that said motor drives the pivoting movement of said rampmember.
 6. A method of assembling a wheelchair ramp subassembly andattaching same to a vehicle having wheelchair access and having avehicle hydraulic system, said method comprising the steps of: providinga wheelchair ramp subassembly frame; providing a ramp pivotably attachedrelative to said frame; providing an electrically driven motor whichdrives a hydraulic pump assembly, both items attached relative to saidwheelchair ramp subassembly frame; providing a rotary actuator attachedto said wheelchair ramp subassembly frame; providing ramp hydraulicswhich form a closed system with said hydraulic pump assembly and saidrotary actuator, said ramp hydraulics not to be commingled with saidvehicle hydraulic system; installing said wheelchair ramp subassemblyframe, said electrically driven motor, said hydraulic pump assembly,said rotary actuator, and said ramp hydraulics, all as a modular unit tosaid vehicle; and connecting electrical power to said electricallydriven motor, such that said electrically driven motor can drive saidhydraulic pump, and said hydraulic pump can pressurize the ramphydraulics such that said rotary actuator operates said pivoting ramp.7. A wheelchair ramp subassembly for use with a vehicle configured toprovide wheelchair access, said vehicle including a wheelchair mountinglocation and also including vehicle hydraulics and hydraulic lines, andsaid wheelchair ramp assembly comprising: a ramp frame; an electricallypowered hydraulic pump assembly attached to frame; hydraulic pumpassembly controls having control lines; and a self-contained ramphydraulic system operably associated with said hydraulic pump assembly,such that said frame of said wheelchair ramp assembly is configured tobe attached to said vehicle in a modular manner and such that saidwheelchair ramp assembly is operable simply by attaching said electricaland control lines to said vehicle, and without the connection of saidramp hydraulic lines with said vehicle hydraulics.
 8. A method ofassembling a wheelchair ramp subassembly and attaching same to a vehiclehaving wheelchair access and having a vehicle hydraulic system, saidmethod comprising the steps of: providing a wheelchair ramp subassemblyframe; providing a ramp pivotably attached relative to said frame;providing an electrically driven motor which drives a hydraulic pumpassembly, both items attached relative to said wheelchair rampsubassembly frame; providing a rotary actuator attached to saidwheelchair ramp subassembly frame; providing ramp hydraulics which forma closed system with said hydraulic pump assembly and said rotaryactuator, said ramp hydraulics not to be commingled with said vehiclehydraulic system; installing said wheelchair ramp subassembly frame,said electrically driven motor, said hydraulic pump assembly, saidrotary actuator, ramp hydraulics, all as a modular unit to said vehicle;and connecting electrical power to said electrically driven motor, suchthat said electrically driven motor can drive said hydraulic pump, andsaid hydraulic pump can pressurize the ramp hydraulics such that saidrotary actuator operates said pivoting ramp.
 9. A method of assembling awheelchair ramp subassembly and attaching same to a vehicle havingwheelchair access, having a vehicle hydraulic system, and having anelectrical system, said method comprising the steps of: providing awheelchair ramp subassembly which includes as an input electrical power,and as an output the control of a pivoting wheelchair ramp to allowselective retraction and extension of said ramp, said wheelchair rampsubassembly including internal, self-contained hydraulics which are notconnected to said vehicle hydraulic system; installing said wheelchairramp subassembly to said vehicle; connecting said electrical system ofsaid vehicle to said electrical input of said wheelchair rampsubassembly; and operating said wheelchair ramp subassembly between aretracted and an extended position.
 10. A wheelchair ramp assembly foruse with a vehicle, said ramp assembly including: a frame member; a rampmember pivotably attached relative to said frame member; an elongatefirst linkage member having opposing first and second ends and alongitudinal axis, said first end pivotably attached to one of saidframe member and said ramp member; said first linkage member defining atransverse bushing hole having an axis substantially perpendicular tosaid longitudinal axis of said first linkage member an elongate secondlinkage member having opposing first and second ends and a longitudinalaxis, said first end pivotably attached to the other of said framemember and said ramp member, said second linkage member definingproximate its second end a transverse bushing hole having an axissubstantially perpendicular to said longitudinal axis of said secondlinkage member, said second linkage member including a transverse pinhole extending through its thickness along the wall, said transverse pinhole having a hole axis being perpindicuar to said longitudinal axis ofsaid second linkage member and also perpendicular to said hole axis ofsaid transverse bushing hole a bushing assembly, said bushing assemblyitself comprising: a main portion, said main portion including a headportion, an intermediate bearing portion, and a fixing portion, saidfixing portion including a through transverse bore configured to accepta length of said pin member; and a pin member configured to extendthrough said transverse bore of said fixing portion and to extendthrough said transverse pin hole of said second linkage member, and toprovide a frictional connection between said fixing portion and saidsecond linkage member, such that when assembled, said pin memberattaches said main portion to said second linkage member, and said firstlinkage member pivots relative to said second linkage member and saidmain portion.
 11. A wheelchair ramp assembly for use with a vehicle,said ramp assembly comprising: a ramp assembly frame configured to bemounted to said vehicle; a ramp assembly pivotably attached relative tosaid frame, said ramp assembly including at least one side wall beingsubstantially platelike and including two opposing primary planarsurfaces; a first linkage member being substantially platelike andincluding opposing primary planar surfaces; a second linkage memberbeing substantially platelike and including opposing primary planarsurfaces; and first and second substantially similar bushing members,each of said bushing members having a head portion defining a top face,said first bushing member mounted such that its top face issubstantially flush with said outside primary planar surface of saidside wall, said second bushing member mounted such that its top face issubstantially flush with the primary planar surface of one of saidlinkage members.
 12. A wheelchair ramp assembly for use with a vehicle,said ramp assembly comprising: a ramp assembly frame configured to bemounted to said vehicle; a ramp assembly pivotably attached relative tosaid frame, said ramp assembly including at least one side wall beingsubstantially platelike and including two opposing primary planarsurfaces; a first linkage member being substantially platelike andincluding opposing primary planar surfaces; a second linkage memberbeing substantially platelike and including opposing primary planarsurfaces; and a bushing member having a head portion defining a topface, said bushing member mounted such that its top face issubstantially flush with the primary planar surface of one of saidlinkage members.
 13. A wheelchair ramp assembly for use with a vehicle,said ramp assembly comprising: a ramp assembly frame configured to bemounted to said vehicle; a ramp assembly pivotably attached relative tosaid frame, said ramp assembly including at least one side wall beingsubstantially platelike and including two opposing primary planarsurfaces; a first linkage member being substantially platelike andincluding opposing primary planar surfaces; a second linkage memberbeing substantially platelike and including opposing primary planarsurfaces; and a bushing member having a head portion defining a topface, said bushing member mounted such that its top face issubstantially flush with said outside primary planar surface of saidside wall.